This invention relates to data transmission in general and more particularly to the fast transfer of bit pattern fields.
In data processing, the problem of evaluating bit pattern fields, to write them into a memory or to call them up from a memory, sometimes arises. Such bit pattern fields are a sequence of binary numbers in which the binary numerals are not considered or used as binary numbers in a fixed format but in which other meanings are assigned to the individual bits, for instance, a switching state (yes/no). Such bit pattern fields, in which the binary numbers are ordered in columns and rows, are found, for instance, in digital testing or in electronic picture analysis and image recognition. In such cases a large volume of data is not uncommon. Such bit pattern fields must be stored, for instance, in an external memory. For this purpose, the external memory is organized in columns and lines, i.e., there are p memory building blocks with a storage depth of z bits, forming z lines, so that each memory building block can be assigned to an output terminal of the test system.
In many bit pattern fields, only a few bits generally change from line to line, i.e., the essential information of the bit pattern field is obtained from changes which occur from line to line. Thus, it is sometimes also customary to characterize bit pattern fields in the form of changes. Sometimes the source data of determined facts are also already given in change form.
In the transmission of data it is otherwise also necessary to control the flow of data by special accompanying signals. Thus, the data lines are provided, for instance, with multi-digit addresses; for determining the switching state of the register, a clock signal, the so-called STROBE signal is used; and as control signal for memory building blocks, the WE signal (meaning "write" or "read") is customary.